The U.S. Government has rights in this invention pursuant to Contract No. DE-ATO3-84SF11963.
The invention relates generally to bearing systems and more particularly to a bearing system wherein a shaft is supported by primary bearings under normal conditions and is supported by backup or secondary bearings upon failure of the primary bearings.
Although not limited to any particular application, the invention will be described in connection with a motor driven turbine. In such applications, the detection of failure of the primary bearings and the automatic shifting of the loads to the backup bearings is justified from cost and safety standpoints.
Bearing assemblies wherein backup or secondary bearings are provided to support loads upon failure of primary bearings are shown and described in U.S. Pat. No. 3,708,215; U.S. Pat. No. 3,454,309; and U.S. Pat. No. 4,425,010. Means for detecting shaft displacement due to bearing wear are disclosed in U.S. Pat. No. 4,434,448.